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Carb Tuning GT550L

Posted: Tue Jan 05, 2021 2:32 am
by Hush
I can't get my tachometer to settle so I am thinking the carb tuning is out, this is a new done nil miles engine, starts first kick, runs happily but bouncing tach tells me something is not right with the air mix. I have tried the old remove 2 plugs and tune the last cylinder but bike won't run on one so that was a fail.

Re: Carb Tuning GT550L

Posted: Tue Jan 05, 2021 5:37 am
by jabcb
How is the tach bouncing around?
Tach problems & tach cable problems can cause the tach to misbehave.

Re: Carb Tuning GT550L

Posted: Tue Jan 05, 2021 7:12 am
by Cliff56
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Re: Carb Tuning GT550L

Posted: Tue Jan 05, 2021 9:47 am
by GTandcbr
Best way to tune the carbs by far is with an airflow meter. Then you know all three are sync'd together.
https://youtu.be/9G5Hsenlv1g

Re: Carb Tuning GT550L

Posted: Tue Jan 05, 2021 10:29 am
by jabcb
Interesting. Don't think I've ever seen one of those meters. Learn something new every day.

Link for the air flow meter? Any particular brand recommended?

Re: Carb Tuning GT550L

Posted: Tue Jan 05, 2021 11:06 am
by GTandcbr
This really does smooth the engine running
https://www.ebay.co.uk/itm/Synchrometer ... 890.l49292
So the proceedure i use is as normal warm the engine first and then remove the airbox.
Get the bike started at tickover then using the meter pushed in the throat of the carb set all 3 carbs to read the same using the cable adjusters on the cap.
Then using the cable adjuster under the twistgrip get engine to rev at 3000 and repeat balancing the carbs.
Then go back to idle and set tickover using throttle valve screws.
This i do every time carbs or airbox is off.
The meter measures how much air each cylinder is sucking and so all three are pulling the same. :o

Re: Carb Tuning GT550L

Posted: Tue Jan 05, 2021 3:48 pm
by Cliff56
I use a manometer on mine and set all three carbs at once.